Our patent application PCT/GB99/00998 describes apparatus for dispensing a volatile liquid into a surrounding atmosphere in which a driving airflow is used to draw the liquid from a conduit by producing a pressure drop in the region of an outlet from the conduit in the manner of a jet pump or venturi. The liquid conduit may be formed as a capillary tube and the airflow may be directed past the conduit outlet region through an air delivery nozzle having a similar size cross-section.
By the use of such devices with small cross-section nozzles, it is possible to achieve rapid dispersal of the liquid into the atmosphere using low mass air flows and to do this by means of a compact device with only a small power requirement. The present invention is concerned with further improvements of devices of this nature.